The invention relates to a calender for a thermoplastic material sheets extruded by an extrusion die via a sheet die.
U.S. Pat. No. 4,997,358 discloses a calender in which more than one roll is provided to smooth and cool the sheet of molten thermoplastic material extruded via the sheet die. The rolls are arranged on a frame. The plastic which is processed to a sheet needs an adaption of the guidance and of the dwell time of the material sheet in contact with the rolls to achieve the required thickness tolerance and required surface of the material sheet. Because of this at least one stationary roll and one adjustable roll, which can be set to different angular settings around the stationary roll, are provided. The adjustable roll is held in guide frames with its ends rotatable and radially adjustable to the stationary roll. The frames can be fixed on both sides of the stationary roll. The frames have discs with circumferentially distributed holes which receive bolts to secure the rolls internal ends. The radial external ends of the frames are attachable to carrier arms of the basic frame by bolts. As the discs act upon the bearings beddings of the stationary roll, they are further loaded. Furthermore, the accessibility of the adjustable roll as well as of the stationary roll is decreased.